Controller for electric motors.



No. 665,!44. Patented Ian. 1901. E. w. STULL.

CONTROLLER FOR ELECTRIC MOTORS.

(Appliantion filed June 16, 1900.

(mi Modal.)

Qmwky ATTORNEY INVENTOR ("8. \m m er n @A 7 Km "m2 "cams PETERS co, wommma, WASNINGYON, v. c

UNITED STATES PATENT ()FFICE.

EMMETT W. STULL, OF JOHNSTOWN, PENNSYLVANIA, ASSIGNOR TO THE LORAIN STEEL COMPANY, OF PENNSYLVANIA.

CONTROLLER FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent N 0. 665,144. dated January 1, 1901.

I A licati filed June 16, 1900. Serial No. 20,545. (No model-J To all whont it may concern:

Be it known that I, EMMETT W. STULL, of Johnstown, in the county of Oambria and State of Pennsylvania, have invented a new and useful Improvement in Controllers for Electric Motors, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

My invention has relation to certain new and useful improvements in controllers for electric motors, and more particularly to so ries-parallel two-motor controllers of that type which employa main moving element ordrum carrying the series-paralleling contacts and also a cut-out switch by means of which either motor, if injured, may be removed from circuit and the remaining motor operated alone.

My invention is designed to provide means of improved character whereby under the condition just stated-that is to say, when but one motor is in circuitthe main element or drum of the controller Will be automatically prevented from being moved beyond its lastseries position, thereby avoiding any confusion of circuits or undesirable circuit conditions which might otherwise occur. This object I accomplish by providing a stop or look for the main moving element or drum, together with an electromagnet, which under normal conditions with both motors in circuit holds said stop in retracted inoperative position, but which when either motor is removed from circuit is thereby deenergized and loses its control of said stop, which thereupon assumes a position to prevent movement of the main element or drum beyond a certain predetermined position.

My invention also consists in the novel construction, arrangement, and combination of parts hereinafter described, and pointed out in the appended claims, reference being had to the accompanying drawings, forming a part of this specification, and to letters of reference thereon.

In the said drawings, Figure 1 is a diagram showing a development in plane of a controller embodying my invention and the circuit connections between the same and a pair of electric motors, and Fig. 2 is a detail viewshowing the stop or locking device and magnet.

The controller shown in Fig. 1 is, in general, of that type manufactured by The L0 rain Steel Company and known commercially as the No. 38 controller. A is the main drum, having the contacts a and cooperating contact-fingers b, and B is a combined reversing and cut-out switch of the rotary type, having contacts 0 and cooperating fingers d. This switch has an intermediate off position and six operative positions, the effects of which are indicated on the drawings, respectively, as Ahead, No. l ahead, No. 1 back, Back, No. 2 back, and No. 2 ahead that is to say, ithas one position in which the car is driven ahead with both motors, another position in which the car is driven back with both motors, and other positions in which the car may be propelled in either direction by either motor alone. The two motors are designated as No. l and No. 2. R indicates artificial resistance for connection in circuit with the motors.

By reference to the diagram it will be readily seen that the conductor P, which connects the sixth finger d of the reversing and cutout switch with the fifth finger b of the seriesparalleling drum, carries no current, except at such times as the reversing and cut-out switch is on either its main ahead or its main back position, since said switch has no contacts for engagement with the said finger d in any of its other positions. In this conductor P, I place an electromagnet M and provide said magnet with a pivoted armature N. Attached to said armature is a spring S, whose normal action it is to hold the armature in such a position that its free end will be in the path of a stop projection 10 on the shaft A of the drum A. This stop projection is definitely positioned with respect to the contacts onthe drum, so as to engage the said armature and stop the drum at a certain predetermined point, which is, preferably, When the drum is at the position indicated by the vertical line 5. This can occur, however, only when the reversing and cut-out switch is at one of its one-motor positions, since when said switch is at either its main ahead or main back posi iions the magnet M is energized and, overcoming the action of the spring S, retracts the armature N out of the path of the stop projection 19.

It will be observed that in the particular controller shown the invention requires no change whatever in the position, arrangement, or number of contacts, and to-apply the invention to any controllerof the general type to which it relates it is necessary only to providethe magnet and stop and to connect the magnet in a conductor which carries current only when both motors are in circuit. If in a particular controller no such conductor is present, additional contacts may be provided for this purpose, and the magnet can then be connected in circuit between them. Various forms of stops may also be employed, since any device arranged to engage a moving part of the main drum and to be retracted from a position of engagement by the action of a magnet is clearly within the scope of my invention. I do not therefore limit myself to the particular construction and arrangement which I have herein shown and described.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In an electric-motor controller, the combination with a conductor which carries current only when all the motors governed by the controller are in use in circuit, of an electromagnet having its coil connected with said conductor, and a stop device for a moving element of said controller arranged to be retracted by said magnet.

2. In an electric controller, having a main moving element provided with contacts and connections for connecting two motors either in series or in parallel, and also a second switch by means of which either of said motors may be cut out of circuit, a stop device for limiting the movement of said main moving element, and a magnet for holding said device inoperative when both motors are in circuit, and for releasing said device when either motor is removed from circuit.

3. In an electric controller, having a main moving element provided with contacts and connections for connecting two motors either in series or in parallel, and also having a switch for cutting either one of said motors out of circuit, of a stop arranged to engage and limit the movement of said main moving element, and an electromagnet for holding said stop in inoperative position, said magnet having its coil connected with a conductor which carries current only when both metors are in circuit.

a. In a controller for two electric motors, the combination with the main moving element, of a stop device for limiting the movement of said element, a magnet for holding said step in an inoperative position, and circuit connections whereby said magnet is active only when both motors are connected in circuit.

In testimony whereof I have al'lixed my signature in presence of two witnesses.

EMMEIT W. SIULL. Vi itnesses: A

BLANOHE SMITH, H. W. SMITH. 

